University of Illinois Urbana-Champaign ATMS 201 exam 2 || All
Answers are Valid.
What are two measures of the absolute amount of water vapor in the air? correct answers Vapor
Pressure and dew point
Define vapor pressure. correct answers Pressure exerted by just the water vapor molecules in the
atmosphere
Define dewpoint temperature. correct answers Lowest temperature that air can be cooled at
constant pressure before condensation will occur
Contours of dewpoint temperature on a surface map appear the same as contours of what other
variable? correct answers Vapor pressure
What do we mean when we state that the atmosphere is saturated? correct answers When the air
in the atmosphere cant hold any more water
Define saturation vapor pressure. correct answers Vapor pressure at a given temperature when air
is saturated
What quantity is directly related to saturation vapor pressure? correct answers Temperature
Define mixing ratio correct answers the mass of water vapor in a unit of air compared to the
remaining mass of dry air
Define saturation mixing ratio. correct answers the mass of water vapor in a unit of saturated air
compared to the remaining mass of dry air
, Define relative humidity in terms of vapor pressure and saturation vapor pressure correct
answers RH = vp/svp
Define relative humidity in terms of the mixing ratio and saturation mixing ratio. correct answers
RH = MR/SMR
In the context of our studies, what is meant by an air parcel? correct answers a volume of air
In the context of our studies, What is meant by "the environment" correct answers Everything
outside the system...in our case, the atmosphere outside the air parcel
In the context of an air parcel, what is meant by an isolated, closed, and open system? correct
answers Isolated system: A system that exchanges neither matter nor energy with its environment
Closed system: A system that does not exchange matter with its environment but allows energy
exchange Open system: A system that allows exchange of both matter and energy with its
environment
What is an ideal gas? correct answers a hypothetical gas whose molecules occupy negligible
space and have no interactions
The form of the ideal gas law for dry air used by meteorologists relates what three variables?
correct answers Pressure, density, and temperature
The form of the ideal gas law for water vapor used by meteorologists relates what three
variables? correct answers Density, temperature, and
Which is denser, moist air or dry air? Justify your answer. correct answers Dry air is more dense,
moist air has less nitrogen and oxygen which is heavier than water molecules
Define virtual temperature. correct answers The temperature that a parcel of dry air would have
if it were at the same pressure and had the same density as moist air.
Answers are Valid.
What are two measures of the absolute amount of water vapor in the air? correct answers Vapor
Pressure and dew point
Define vapor pressure. correct answers Pressure exerted by just the water vapor molecules in the
atmosphere
Define dewpoint temperature. correct answers Lowest temperature that air can be cooled at
constant pressure before condensation will occur
Contours of dewpoint temperature on a surface map appear the same as contours of what other
variable? correct answers Vapor pressure
What do we mean when we state that the atmosphere is saturated? correct answers When the air
in the atmosphere cant hold any more water
Define saturation vapor pressure. correct answers Vapor pressure at a given temperature when air
is saturated
What quantity is directly related to saturation vapor pressure? correct answers Temperature
Define mixing ratio correct answers the mass of water vapor in a unit of air compared to the
remaining mass of dry air
Define saturation mixing ratio. correct answers the mass of water vapor in a unit of saturated air
compared to the remaining mass of dry air
, Define relative humidity in terms of vapor pressure and saturation vapor pressure correct
answers RH = vp/svp
Define relative humidity in terms of the mixing ratio and saturation mixing ratio. correct answers
RH = MR/SMR
In the context of our studies, what is meant by an air parcel? correct answers a volume of air
In the context of our studies, What is meant by "the environment" correct answers Everything
outside the system...in our case, the atmosphere outside the air parcel
In the context of an air parcel, what is meant by an isolated, closed, and open system? correct
answers Isolated system: A system that exchanges neither matter nor energy with its environment
Closed system: A system that does not exchange matter with its environment but allows energy
exchange Open system: A system that allows exchange of both matter and energy with its
environment
What is an ideal gas? correct answers a hypothetical gas whose molecules occupy negligible
space and have no interactions
The form of the ideal gas law for dry air used by meteorologists relates what three variables?
correct answers Pressure, density, and temperature
The form of the ideal gas law for water vapor used by meteorologists relates what three
variables? correct answers Density, temperature, and
Which is denser, moist air or dry air? Justify your answer. correct answers Dry air is more dense,
moist air has less nitrogen and oxygen which is heavier than water molecules
Define virtual temperature. correct answers The temperature that a parcel of dry air would have
if it were at the same pressure and had the same density as moist air.
